CD-Sextant - Build your own sextant - Pole Shift Survival Information

Navigator Light Software
Tips for scanning charts
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Scan using resolutions between 75 and 150 dpi. Avoid large files (over 1MB GIFs or JPGs). Images will have to be
ressampled by the Navigator at run time while zooming. Large images will consume a lot of CPU cycles, resulting in
poor and bumpy performance.
When scanning large paper charts, you may detach the page scanner cover (if the scanner allows) to avoid folding the
chart. Put some weight over the scanner cover, so that the paper is flat and perfectly in contact with scanner bed.
If the chart doesn't fit in the scanner bed, scan it in parts, overlapping between them. Then make a CID file for each
image. Navigator can display different charts together, and will even allow partially opaque rendering, merging the
overlaps.
Larger scanners (A3) are preferred, when available. A4 scanners are small for large paper charts.
Hand scanners are not recommended, because they can distort the image scale. Use only page scanners.
Images should be saved in GIF or JPG format (JPG is usually better).
Choosing the 3 reference points
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The 3 reference points indicate how the pixels in the chart image map to the actual world. Care must be taken in choosing
these points, in order to achieve a precise scale. Below are some guidelines for choosing the reference points:
Choose reference points that are as far from each other as possible. This will result
in a more precise scale. If possible, choose points near the corners of the image. In
the image on the left, points are too close and the scale will be poor.
bad points- too close!
http://www.tecepe.com.br/nav/navpro.htm (20 of 23) [9/2/2004 11:05:07 PM]